Fluid force applying device

ABSTRACT

A WORK HOLDING CLAMP IN THE NATURE OF A SELF-CONTAINED HYDRAULIC CYLINDER-PISTON UNIT IN WHICH ONE OF THE FORCE APPLYING MEMBERS, FOR EXAMPLE THE PISTON OR RAM, IS ROTATABLE AND AXIALLY MOVABLE IN ITS FORCE-APPLYING STROKE.

March 23, 11971 w, SEESODY 3,572,215

FLUID FORCE APPLYING DEVICE Filed April 23, 1969 A56 00 24 B4 Q /32 v M4#4 W lNl/l/VTOR 0. M 5:53 00 MGM J Miran [y United States Patent O US.Cl. 9233 8 Claims ABSTRACT OF THE DISCLOSURE A work holding clamp in thenature of a self-contained hydraulic cylinder-piston unit in which oneof the force applying members, for example the piston or ram, isrotatable and axially movable in its force-applying stroke.

BACKGROUND It has long been common practice to provide hydraulicallyactuated single or double acting cylinder-piston or ram devices for usein applying force in an axial direction in the accomplishment of diversework. In some instances, the force application has been a pushing orspreading force, and in other instances, it has been a pulling force.

It has also been heretofore proposed to provide swingable clampingdevices which utilize means such as a helical spline connection betweenrelatively movable members for imparting rotation to the clamp carrieras it is moved axially, and it is not uncommon to utilize hydraulicpower for actuating such clamping devices.

However, in all known instances, these swingable clamping devices haveconsisted of separate structures and have been entirely independent ofthe power or force applying devices used to actuate the same. Thus, theprior clamps and their attendant actuators have been undesirably bulky,and have moreover required the use of external mechanisms such assprings and/or the use of multiple hydraulic systems. Furthermore, theneed for purchasing the swing clamp as a separate attachment resulted inadded expense, and these attachments were rather restricted in theirapplications and use.

Also, in the prior swingable clamp structures, the splining between therelatively movable members has generally been such as to cause rotationof the clamp carrying member for the full axial movement thereof.Accordingly, the axial clamping forces imparted by the clamp throughoutits effective stroke have heretofore been distorted and otherwiseadversely affected by the accompanying rotational movement thereof, thusfurther increasing the frictional resistance to which the clamp isexposed.

SUMMARY OF THE INVENTION It is accordingly a primary object of thepresent invention to provide a force mechanism which obviates all of theaforesaid objections and disadvantages of prior devices of this generaltype.

Another object of this invention is to provide an improved forcemechanism which indexes a given number of degrees in a circular arc andthereafter drives straight ahead solely in an axial direction.

Still another object of the invention is to provide an improvedhydraulic force applying device which is entirely self-contained in anexceedingly compact and unitary package without need for any externalsprings or other external mechanisms and without using multiplehydraulic systems.

A further object of the present invention is to provide a forcemechanism which is especially adaptable for use as a hydraulic swingclamp but which may be readily adapted for either pull or push types oflinear actuation,

3,5722% Patented Mar. 23, 1971 single or double-acting types ofhydraulic systems, use with clamping arms of diverse types and varyinglengths, and use with hydraulic cylinder-piston devices having either asolid or a hollow piston.

Force applying devices embodying the present improvements comprisegenerally, a body having a central bore, a cylindrical guide membernon-rotatably confined within the bore of said body and having a camslot formed in the cylindrical exterior thereof, a piston having aportion slidably confined within the bore of said body and having a boreslidably received by the cylindrical guide member, a cam followercarried by the piston and operable in the cam slot of the guide memberto guide the piston in its movement, and means for axially displacingthe piston along the bore of said body.

These and other objects and advantages of the invention will becomeapparent from the following detailed description.

THE DRAWINGS A clear conception of the several features of the presentinvention and of the mode of constructing and of operating a typicalswing clamp embodying the improvements may be had by referring to thedrawings accompanying and forming a part of this specification whereinlike reference characters designate the same or similar parts in theseveral views.

FIG. 1 is a central longitudinal section through a typical swing clamphaving a single acting hydraulic ram and embodying the features of thepresent invention, the piston and clamp being shown in fully extendedposition;

FIG. 2 is a similar section through the device of FIG. 1 but showing thepiston and clamp in indexed and clamping position;

FIG. 3 is a central longitudinal section through another embodiment of aswing clamp wherein the ram is of the double acting hydraulic type andthe guide member is hollow, the piston and clamp again being shown infully extended position; and

FIG. 4 is a plan view of the swing clamp with the clamping arm beingshown as swung to indexed and clamping position by means of brokenlines.

DETAILED DESCRIPTION While the invention has been shown and describedherein as being embodied in a swing clamp of a particular constructionwherein the clamping element is indexed in a circular arc and then isdriven straight downwardly in its clamping stroke, it is not intended ord sired to unnecessarily restrict or limit the invention by reason ofsuch specific embodiments since the improvements may be used toadvantage in other types of force applying devices which include areciprocating piston and in which advantages may be obtained by rotatingthe piston during its movement. It is also contemplated that certaindescriptive terms used herein shall be given the broadest possibleinterpretation consistent with the disclosure.

Referring to FIGS. 1 and 2 of the drawings, the typical force applyingdevice shown therein as embodying the invention comprises generally abody 10 formed with a central bore 12 slidably receiving the enlargedportion 16 of a piston 14.

The body 10 is provided with a radial port 18 entering the bore 12 onone side of the portion 16 f the piston, the port 18 being formed in acustomary manner to receive an inlet fitting adapted to be connected t asuitable source of supply of pressurized hydraulic fluid so thathydraulic fluid under pressure may be Selectively supplied to the bore12 to forcibly axially displace the piston within the bore of the body10. The portion 16 of the piston 14 is also provided with the usualannular groove and seal 20, and the reduced portion of the piston 14 isembraced in the usual manner by a suitable sealing ring 22 confinedwithin an annular groove at the end of the bore 12 of the body 10.

In the embodiment shown in FIGS. 1 and 2, the piston 14 is displacedaxially downwardly by fluid under pressure supplied through the port 18,and a coil spring 24 compressed between the underside of the pistonportion 16 and the base 26 of the body serves to return the piston toits extended position upon release of pressurized fluid to the upperportion of the bore 12. It is also preferable to place the spring 24 intorsion during movement of the piston and compression of the spring, foraccomplishing this purpose, the upper end of the spring is suitablyattached as at 28 to the piston portion 16 and the lower end of thespring 24 is attached as at 30 to the base 26.

The base 26 may be suitably secured to the end of the body 10 as bymeans of an annular series of machine screws 32 or the like, and thehydraulic force applying device is thus of unitary structure and isentirely selfcontained.

In accordance with the present invention, provision is made for causingrotation or indexing of the piston 14 during its axial movement, suchrotation of the piston serving to swing a clamping arm 34 or the likesecured to the outer extending end of the piston 14 as by means of abolt 36 through a desired number of degrees shown in the presentinstance as 90. Thus, the clamping arm 34 which may be provided with awork engaging saddle 38 or the like is swung out of the way of the workupon extension of the piston 14 with the clamp being swung into workingengagement upon power movement of the piston.

To perform the indexing operation, a cylindrical guide member or post 42is non-rotatably confined within the bore 12 of the body 10, the post 42being shown as secured at one end within a central aperture 44 of thebase 26 as by means of a pin or pins 46. The cylindrical exterior of theguide member 42 is formed with a cam slot 48 of a configuration such aswill give the desired indexing to the piston 14 as will hereinafterbecome apparent.

The piston 14 is formed with a central bore 52 slidably received by theinner end of the guide member 42, and a cam follower 54 is carried bythe piston 14 so as to be operable in and along the cam slot 48 of theguide member 42 to guide the piston 14 in its movement. As shown, thecam follower 54 may conveniently comprise a ball seated within a detent56 formed in the bore 52 of the piston 14.

In the embodiment shown, the piston 14 is moved downwardly uponintroduction of fluid under pressure via port 18 to the displacementchamber formed by the bore 12, and as it moves downwardly, the pistonsimultaneously indexes in a circular motion to move it through a 90 arcby reason of the ball 54 which operates in the cam groove 48. At the endof the 90 index or such other degree of are as might be desired, thepiston will be caused to move in a straight line as the ball 54 followsthe straight portion 58 of the cam groove. Thus, during the firstportion of its travel, the clamping arm 34 is swung from an inactiveout-of-the-way position to a position wherein it is aligned with thework, and during the straight terminal portion of its movement, aclamping force is provided which is not in any way distorted orotherwise adversely affected by torsional strains. After the clampingoperation is completed and the hydraulic pressure is released from theupper end of the pressure chamber, the piston is free to move upwardlyand such movement is provided in the embodiment of FIGS. 1 and 2 by thecompression spring 24. During its return stroke, the piston 14 obviouslyinitially moves in a straight upward path and subsequently indexes in anare as provided by the cam 48 back to its starting position whereby theclamp 34 is out of the way of the work to permit unobstructed access tothe work.

Referring now to FIG. 3, the force applying device shown therein isessentially the same as that shown in FIG. 1 except that hydraulicpressure is used for actuating the ram in both directions and the guidemember is formed hollow for the reception of suitable implements.However, the device still includes a body formed with a central bore 112which slidably receives the enlarged portion 116 of the piston 114.

The body 110 is again provided with a radial port 118 entering the bore112 about the portion 116 of the piston, and the usual seals 120 and 122are again provided for sealing between the piston and the body.

However, instead of the spring for returning the piston to extendedposition, the body 110 is formed with a second radial port 124communicating with the lower portion of the chamber formed by the bore112 below the enlarged portion 116 of the piston. Thus, the piston isextended by introducing pressurized fluid via port 124 to the lowerportion of the chamber 112, and the piston is moved axially downwardlytoward clamping position by exhausting fluid from port 124 and admittingpressurized fluid through port 118 to the chamber 112 above the pistonportion 116.

In the device of FIG. 3, the base 126 may again be suitably secured tothe end of the body 110 as by means of an annular series of machinescrews 132 or the like, and an annular seal is preferably provided forsealing between the end of the body 110 and the base 126. Also, sincethe device of FIG. 3 is fully pressurized for actuation of the piston inboth directions, it is preferable to provide a seal 128 between the bore152 of the piston and the exterior of the guide member 142.

The piston 114 of the device shown in FIG. 3 is again rotatable during aportion of its axial movement, and the extending end thereof may beprovided with a suitable clamping arm 134 as hereinabove described withreference to FIGS. 1 and 2. The clamping arm 134 may be suitably securedas by means of a bolt 136 to the end of the piston, and the extendingend of this arm may be provided with a suitable work-engaging saddle 138or the like, Once again, the indexing operation is performed by means ofa cylindrical guide member 142 non-rotatably confined within the bore112, and in this instance, the guide member 142 is shown as being in thenature of a tube or hollow cylindrical member which may be suitablyadapted to receive any desired implement. The tubular guide member 142is again preferably secured within a central aperture 144 of the base126 as by means of pins 146, and the cylindrical external surface of themember 142 is formed with a cam slot 148 of desired configuration.

The piston 114 is formed with a bore 152 slidably received by the end ofthe guide member 142 and a cam follower 154 is seated within a detent156 formed in the bore of the piston 114. A convenient cam follower isagain shown as being in the nature of a ball seated within the detent156, the ball being operable in and along the cam slot 148 ashereinabove described, the arcuate portion 148 of the cam slotterminating in a straight portion 158 so that the clamp will follow astraight line path after indexing in an arcuate path for performance ofthe clamping action.

I claim:

1. A work holding swing clamp comprising a body having a central bore,

a cylindrical guide member fixed within the bore of said body, saidmember having a cam slot therein including an arcuate portion and astraight terminal portion,

a piston assembly having a first portion slideably confined within thebore of said body and also having a second portion extending outwardlyof said body in slideable and sealable contact therewith,

a clamp arun secured to said outwardly extending portion,

a cam follower carried by said piston assembly and 0perable in said camslot of said guide member to impart a rotary motion to said pistonassembly on movement of said cam follower through said arcuate portionof said cam slot and axial motion to said piston assembly on movement ofsaid cam follower through said straight terminal portion of said camslot, and

means for axially displacing said piston assembly along the bore of saidbody.

2. The clamp according to claim 1 wherein the cam follower includes aball element confined partially within a detent formed in said pistonassembly.

3. The clamp according to claim 1 wherein said means for axiallydisplacing said piston assembly along the bore of said body includes apressurized fluid acting on said piston assembly in one direction and aspring acting on said piston assembly in the opposite direction.

4. The clamp according to claim 1 wherein said means for axiallydisplacing said piston assembly in both directions includes apressurized fluid admitted selectively to opposite sides thereof.

5. The clamp according to claim 1 wherein said cylindrical guide memberis a hollow, open-ended tube.

6. The clamp according to claim 1 wherein said body is provided with abase and said cylindrical guide member extends through an aperture inthe base and centrally into said bore of said body.

7. The clamp according to claim 1 wherein said piston assembly has abore therein slideably received by said cylindrical guide member.

8. A work holding swing clamp comprising a body having a central bore,

a hollow open ended guide member fixed within the bore of said body,said member member having a cam slot therein including an arcuateportion and a straight terminal portion,

a piston assembly having a first portion slideably confined Within thebore of said body and a second portion extending outwardly of said bodyin slideable and scalable contact therewith,

a clamp arm secured to said outwardly extending second portion,

a cam follower carried by said piston assembly and operable in said camslot of said guide member to impart a rotary motion to said pistonassembly on movement of said cam follower through said arcuate portionof said cam slot and axial motion to said piston assembly on movement ofsaid cam follower through said straight terminal portion of said camslot, and

means for admitting a pressurized fluid selectively to opposite sides ofsaid piston assembly to axially displace said piston assembly along thebore of said body.

References Cited UNITED STATES PATENTS 1,602,209 10/1926 Proell 92-31X2,752,801 7/1956 Olson 269-93X 3,339,463 9/1967 Updegrave 92-313,457,838 7/1969 Rowe 92-33 2,117,225 5/ 1938 Stein 92-33 2,806,4509/1957 Geyer 92-33 2,883,144 4/1959 Kendig 92-33X 2,938,399 5/1960Briggs 92-33X 3,046,802 7/1962 Cupedo 92-31X 3,207,468 9/1965 Lauducciet al 92-31X 3,218,937 11/1965 Dettlof 92-33X 3,255,806 6/1966 Meyer eta1 92-33X 3,397,879 8/1968 Morawski et a1 269-91 3,450,382 6/1969 Calim92-31 3,453,938 7/ 1969 Fewel 92-33 FOREIGN PATENTS 47,661 Germany 92-33221,843 5/1910 Germany 92-33 290,306 9/1913 Germany 92-33 MARTIN P.SCHWADRON, Primary Examiner L. I. PAYNE, Assistant Examiner U.S. Cl.X.R. 74-55; 269-91

